Testing system



w. a. BLAUVELT. TESJING SYSTEM? APPLICATION/FILED m1. 8. 1919.

Patented Feb. 14, 1922 //7 van for W/'///'am G. B/m/ve/t UNITED STATES PATENT OFFICE.

WILLIAM Gr. BLAUVELT, 015 NEW YORK, N. 'Y., ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OE NEW YORK.

'rns'rrne SYSTEM.

Specification of Letters Patent. Patented Feb, 14, 1922,

Application filed. January 8, 1919. Serial No. 270,205.

To all whom it may concern:

Be it known that I, VVILLIAM G. BLAU- VELT, residing at New York, in the county of New York and. State of New York, have invented certain Improvements in Testing Systems, of which the following is a specification.

This invention relates to testing systems,

and more particularly to such systems emheretofore employed, it has been the prac-.

tice to provide at the switchboards special trouble or hospital positions in whichappear multiple terminals of all telephone lines terminating at the exchange and cord circuits connected with sources of tone supply for connection with the multipled terminals of any desired line or lines which may be in trouble. In such prior systems, the operator at the trouble or hospital position, upon being informed that a telephone line is in trouble, connects one of the cord circuits.

with the multiple terminals of the particular line, thereby connecting the'source of tone supply with all test terminals of. that line throughout the exchange. This cord circuit remains so connected until the line is cleared of the trouble; The production of this particular tone in the receiver of an operator when making a test of the tele phone line is a signal indicating that the line is in trouble and that no connections are to be established therewith.

It is the object of the present invention to simplify such system by providing means for connecting such sources of tone supply with the telephone lines independently of the switchboards and associated apparatus at which the lines terminate. In attaining the object of this invention a common busbar to which a source of tone supply is connected is located adjacent stationary terminals of a group of telephone lines pref.- erably situated in theterminal room of the exchange so thatconnection may be readily and easily made between the test terminal of any line of the group and the common bus-bar. This connection is preferably made by means of a conductor to each end oi which is connected a terminal clip -lfor engaging the common bus-bar and the test terminal of the telephone line.

A more complete understanding of this invention may be obtained from the following description when considered in connection with the accompanying drawing, in which one embodiment of the invention is illustrated in connection with a semi-automatic telephone system.

In the organization illustrated in the drawing, a metallic telephone line A is shown extending from a subscribers station to the central office or exchange where it terminates upon stationary contact terminals of a plurality of automatic line finder switches B, C and D, and on the contacts of a plurality of multiple connecting jacks, such as E positioned in various sections of a switchboard at which are stationed operators for completing connections between calling and called lines. It will, of course, be understood that many telephone lines similar to A terminate at the exchange, but

for convenience the one line only is shown. Likewise, only one brush set of the line finders is lllustrated, and with this brush set F there is suitably associated a cord circuit G by means of which an operator may complete connections with a called telephone line. Each telephone line has connection at the central oflice through the normally closed contacts of a cut-off relay 4 with the windings of a line relay 5. lVhen the line relay 5 is energized it connects ground to the conductor 6 which is the starter or control conductor for the automatic line finder switches. The apparatus controlled over this starter conductor for controlling the operation of the line finder switches may be of any suitable type, such, for example, as that shown and described in a copendin application of Samuel B. 7Williams, J11, Serial No. 180,634, filed July 14:, 1917. Since the control apparatus of the. line finder switches forms no part of this invention, a furtherdescriptionthereof will be omitted. I

The automaticline finder switchesillustrate'd are of the so-called panel type in plurality of finder switches on which the telephone lines terminate are mounted on a vertically'disposed flatpanel. When any of thetelephone lines terminating at the central otiice are reported in trouble, as when the line wires are crossed or grounded or one of the line wires is open, it is desirable that this he made known to all connecting operators at the central oihce. A very effective way for making this known to the operators is to connect with the test terminals of the line or lines in trouble a source of tone supply, by means of which a special tone is produced in the receiver of an operator when mak ing a test of the line just prior to the act of establishing connection therewith which serves as a signal to the testing operator indicating that the line is in trouble and that no connection is to be established therewith so long as the source of tone supply remains associated with the test terminals thereof.

In accordance with the present invention the source of tone supply is associated with the test terminals of the line or lines in trouble in the following manner: Adjacent one end of the bank or panel of stationary contact terminals forming a portion of the line finder switches, there is provided a busbar 10 which is common to such line finder switches. A source of tone supply compris mg a battery 11 and an interrupter 12 con.

nected in series with the primary winding 13 of a transformer whose secondary 14 is connected with the bus-bar 10 by means of a conductor 15 is provided at the central oflice for producing the special indicating tone in the receiver of a testing operator.-

In order that the test terminals of any line or lines may be connected with the bus'bar 10, there is provided a plurality of insulated flexible conductors, such as'16. To each end of each flexible conductor 16, there 18 connected a terminal clip 17 adapted to clampthe bus-bar 10 and a test terminal of the line in trouble. A separate test terminal for each line may be provided on the panel or, as illustrated in the drawing, the end line finder switch may be left unequipped with a brush set, whereby the terminal clips 17 may be readily clamped onto the test terminals. The source of tonesupply is thereby or when many lines are in trouble as is occasionally the case in times of severe storms, the test terminals of all such lines may be connected with the source oftone supply. The only equipment necessary is a supply of terminal clip-ended flexible cords 16. 1

Assuming that telephone line A is in trouble, thetest terminal 20 thereof will be connected with the bus-bar 10 by means of the clip ended flexible conductor 16, and the source of tone supply will be connected with all test terminals of this line. Assuming also that an operator has been advised by a calling subscriber that connection is de sired with telephone line A, the operator makes a test of this line by bringing the tip contact of the plug 21 into engagement with the sleeve or test terminal of the jack, whereupon a spacial tone is produced in the operators receiver 22 due to a flow of current from the grounded bus-bar 10 through the terminal clip 17, conductor 16, the other terminal clip 17, test terminal 20, sleeve contact of the jack E, tip contact of the plug 21, normal contact of the relay 2 1 and the tertiary winding of the induction coil 23 associated with the operatorstelephone set, which induces current in the circuit including the operators receiver. i

What is claimed is:

1. In a testing system for telephone exchanges, in combination, a plurality of telephone linesarranged in groups, connecting jacks for the lines provided in a switchboard at the telephone exchange, test terminals for each line multiplied to the corresponding jacks, a bus-bar common to the test terminals, a source of tone supply connected with the bus-bar, and means for electrically connecting any one or all of the test terminals with the bus-bar.

2. In a testing system for telephone exchanges, in combinatioma plurality of telephone lines arranged in groups, connecting jacks for the lines provided in a switchboard at the exchange, test terminals for each line multipled to the corresponding connecting jacks, a bus-bar common to the test terminals, a source of tone supply connected with the bus-bar, and means including a conductor and associated terminal clips for connecting any one or all of the test terminals with the bus-bar.

3. In a testing system for telephone exchanges, in combination, a plurality of telephone lines arranged in groups, connecting jacks for the line provided in a switchboard at the exchange, test terminals for the lines multipled to the corresponding connecting jacks, a panel in which the test terminals are mounted, a bus-bar adjacent the panel, a source of tone supply connected with the bus-bar, and a connecting link including terminal clips for electrically connecting having stationary line and test terminals for the telephone lines, a. supporting panel in which the terminals are mounted, a bus-bar common to the line finder switches, a source of tone supply connected with the bus-bar,

and means including a conductor and connected terminal clips for electrically connecting the test terminal of one of the lines with the bus-bar.

In testimony whereof, I have signed my name to this specification this 3rd day of January, 1919,

\VILLIAM G. BLAUVEL'II. 

